Leaking return lines

Ddizzy77 · Dec 10, 2017

Hi, one of my return line caps was leaking. Replaced the o rings and no more leaks... so far. But, now it seems I have an air intrusion problem. Tried to start my truck, ran a few seconds and died. Turned it over a few times and it fired up, rough then smoothed out. Not sure next steps. Replaced the return lines and o rings last year, newer lift pump. Only thing I'm thinking is the rubber return lines weren't cut very clean. Maybe replace the lines again? Where can I find those little spring clamps? 1993 f250 7.3 idi NA.

Thanks

Sidewinded_idi · Dec 11, 2017

@typ4

franklin2 · Dec 11, 2017

You need to look the system over very carefully. Look for any dampness around the caps, around any fuel lines up front, any return lines and check the top of the fuel filter, there is a o-ring around the fuel heater that can let air in. Not always but usually there will be slightly wet looking around were the air is going in.

If you have a area you are not sure about, get some brake cleaner and spray it, the cleaner will quickly dry it out. Then monitor it and see if it gets damp again. This stuff also works well for tracing oil leaks.

Clb · Dec 11, 2017

Ok
Disclaimer....
I am knee deep in empty's
1 post, no search, no intro, no problem.

Its time for new returns.
And some reading.
It is all here for the time you spend reading.
Or we could hold your hand on the MOST common thread here????

Bahahaha velcomen

IDIBRONCO · Dec 11, 2017

When did you have this problem? If you had it right after replacing the o-rings, then that is normal. You opened the fuel system and the fuel drained back to the tank. Does it still do this after you've cleared all of the air out of the system?

Ddizzy77 · Dec 11, 2017

I replaced them a year ago, started dipping into the 20s recently. Cap was leaking, replaced the orings on that one. Ran it, no leaks. A little strange, everything was fine for the last year. Think new orings all around?

Ddizzy77 · Dec 11, 2017

Clb said:
Ok
Disclaimer....
I am knee deep in empty's
1 post, no search, no intro, no problem.

Its time for new returns.
And some reading.
It is all here for the time you spend reading.
Or we could hold your hand on the MOST common thread here????

Bahahaha velcomen

My hands have been cold lately

Macrobb · Dec 11, 2017

Just slap a check valve between the lift pump and the fuel filter and call it good.
The lift pump internal flappers don't work perfectly as check valves forever... and if they get any crud in there, you get some 'drainback' if /any/ air can get in.

With a check valve to keep the /supply/ fuel in place, it doesn't matter what happens on the return side.

Personally, I just grab one of those squeeze-bulb primer bulbs. Internally, they are two check valves, and they are cheap. Plus, added manual primer if you need it.

Ddizzy77 · Dec 11, 2017

Macrobb said:
Just slap a check valve between the lift pump and the fuel filter and call it good.
The lift pump internal flappers don't work perfectly as check valves forever... and if they get any crud in there, you get some 'drainback' if /any/ air can get in.

With a check valve to keep the /supply/ fuel in place, it doesn't matter what happens on the return side.

Personally, I just grab one of those squeeze-bulb primer bulbs. Internally, they are two check valves, and they are cheap. Plus, added manual primer if you need it.

Hmm, I replaced the lift pump three or so years ago. When I get a chance I'll try it.

Ddizzy77 · Dec 11, 2017

IDIBRONCO said:
When did you have this problem? If you had it right after replacing the o-rings, then that is normal. You opened the fuel system and the fuel drained back to the tank. Does it still do this after you've cleared all of the air out of the system?

Yup still does it. Replaced the leaking orings. Now it seems like air intrusion. My rear tank is also leaking, looks like it's coming from the top.

IDIBRONCO · Dec 11, 2017

It may not hurt to replace the rest of the o-rings then. I'd think that they should be alright since they are only a year old, but there was another injector that had leaking o-rings that were a year old.

Ddizzy77 · Dec 11, 2017

IDIBRONCO said:
It may not hurt to replace the rest of the o-rings then. I'd think that they should be alright since they are only a year old, but there was another injector that had leaking o-rings that were a year old.

Thanks, I was thinking that. Seems like everything started leaking at the same time

franklin2 · Dec 12, 2017

Macrobb said:
Just slap a check valve between the lift pump and the fuel filter and call it good.
The lift pump internal flappers don't work perfectly as check valves forever... and if they get any crud in there, you get some 'drainback' if /any/ air can get in.

With a check valve to keep the /supply/ fuel in place, it doesn't matter what happens on the return side.

Personally, I just grab one of those squeeze-bulb primer bulbs. Internally, they are two check valves, and they are cheap. Plus, added manual primer if you need it.

How can that work when you have that return line going down the rear of the engine to the tanks? That is a major highway for the fuel to return to the tanks if air gets in somewhere.

I don't know why anyone hasn't tried it yet, but I always thought a electric solenoid valve in the return line would help stop this. Activate it with the key in run, turn it off and block the return line when the key is off.

I believe the factory already has a check somewhere in the feed system on the pass side front. Not sure if it's in the filter head or somewhere else.

typ4 · Dec 14, 2017

Hey, I sell complete return kits, high quality. Just sayin.

Pork_Chop50 · Dec 14, 2017

And also the lines themselves can check and crack over time. I've replaced my hoses twice now along with caps and o-rings. I would take typ4 up on the offer and start over with a whole new setup. The fuel heater o-ring and injection pump line olives should be replaced as well.

Leaking return lines

Ddizzy77

Registered User

Sidewinded_idi

Full Access Member

franklin2

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Clb

Another old truck

IDIBRONCO

IDIBRONCO

Ddizzy77

Registered User

Ddizzy77

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Macrobb

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Ddizzy77

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Ddizzy77

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IDIBRONCO

IDIBRONCO

Ddizzy77

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franklin2

Full Access Member

typ4

Supporting Member

Pork_Chop50

He looks kinda hairy and slobbery to me....

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